The invention concerns an amplifier for timed electrical measurement signals on which is superposed a relatively high spurious DC voltage, ie noise, and which are fed to an analog-digital converter.
In known devices of this kind, illustratively magnetically-inductive flowmeters, optical sensors and the like, spurious voltages may arise. This is especially so for flowmeters wherein spurious DC voltages up to .+-.1 v may arise on account of contact potentials which then are superposed on the DC test signal proper. However as the DC signal is of a magnitude roughly from 10 to a maximum of 2,000 uv (microvolts), analyzing test signals with such noise will be difficult.
In particular such a device requires using an analog-digital converter of very high resolution. In turn, however, this high resolution renders such analog-digital converters very expensive, and such a transducer therefore will not be useful in many applications.